Follow these simple steps to create your delicious Cheesy Tuna and Broccoli Rice:

1. Cook the Rice: In a medium saucepan, combine the 1 cup of uncooked long-grain white rice with 2 cups of chicken or vegetable broth. Bring to a boil, then reduce heat to low, cover, and simmer for 15-20 minutes, or until all the liquid is absorbed and the rice is tender. Fluff with a fork and set aside.
2. Preheat Oven & Prepare Baking Dish: Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish or a similar-sized casserole dish.
3. Sauté Aromatics & Broccoli: While the rice is cooking, heat the olive oil in a large skillet or Dutch oven over medium heat. Add the chopped onion and sauté until softened and translucent, about 5-7 minutes.
4. Add Garlic & Broccoli: Stir in the minced garlic and cook for another minute until fragrant. Add the broccoli florets to the skillet. Cook for 3-5 minutes, stirring occasionally, until the broccoli is tender-crisp and bright green. You want it slightly undercooked as it will continue to cook in the oven.
5. Combine Wet Ingredients: In a large mixing bowl, whisk together the condensed cream of mushroom soup and the 1/2 cup of milk or chicken broth until smooth.
6. Add Seasonings & Tuna: Stir in the salt, black pepper, and dried thyme or Italian seasoning (if using) into the soup mixture. Gently fold in the drained and flaked tuna.
7. Incorporate Rice & Vegetables: To the bowl with the tuna mixture, add the cooked rice and the sautéed broccoli and onion mixture. Stir gently to combine everything thoroughly, trying not to break up the tuna too much.
8. Add Cheese: Stir in 1 cup of the shredded cheddar cheese until it’s evenly distributed throughout the mixture.
9. Transfer to Baking Dish: Pour the entire mixture into the prepared baking dish and spread it out evenly.
10. Top & Bake: Sprinkle the remaining 1/2 cup of shredded cheese evenly over the top. If using breadcrumbs, toss them with the melted butter (if using) in a small bowl, then sprinkle them over the cheese.
11. Bake: Bake in the preheated oven for 20-25 minutes, or until the casserole is hot, bubbly, and the cheese topping is melted and golden brown. If the top starts to brown too quickly, you can loosely tent it with aluminum foil.
12. Rest & Serve: Remove from the oven and let the casserole rest for 5-10 minutes before serving. This allows the flavors to meld and the casserole to set slightly, making it easier to serve.